INGREDIENTS & RESEARCH

Cranberry

BACKGROUND

Ingredient Type: Botanical

Also Known As: Vaccinium macrocarpon, American cranberry

Cranberry is a plant from the Ericacae family that is native to the Northwestern United States and Canada.  It was likely first discovered and used by the Native Americans and was later wholeheartedly adopted by European settlers.  While it is generally believed to be useful in the treatment and prevention of urinary tract infections, there is limited evidence to support its use for the treatment or prevention of other diseases including cancer, diabetes, and cardiovascular disease.

The name “cranberry” is said to be derived from the pilgrim name “craneberry” due to the resemblance of the cranberry fruit and blossom to the head and bill of a sand crane (1).

 

TRADITIONAL USES

Native Americans were likely the first peoples to discover the various uses of cranberries.   Although they used cranberries in a range of different foods, it was most popular in a dish named pemmican; which consisted of crushed cranberries, dried deer meat, and melted fat.  Native Americans also used cranberries for treating arrow wounds, and dying rugs and blankets (1).

European settlers adopted some of the traditional Native American uses of cranberries and found that they were also useful as a tool for bartering.  Eventually, American whalers and mariners brought cranberries with them on their voyages as a way of preventing scurvy (1).

 

WHAT DOES SCIENCE TELL US?

  Cranberries Might Help Support a Healthy Urinary Tract:

A 2016 study looked at the connection between a cranberry extract that has a high proanthocyanidins (PACs-A) content and prevention of UTIs (2).  In the study, females ranging from ages 19 to over 51 and males over the age of 51 were divided into two balanced groups.  The experimental group was given 1 capsule containing the extract (36 mg PACs-A) twice each day in the morning and evening for a week. The results found that in the age range of 31-35 only a slightly significant difference was found between the cranberry extract and the placebo (p=0.095), whereas all other female groups showed a significant difference (<.001). When analyzed together, both the male and female groups showed a significant difference (p<.001) (2).

Another study assessed the benefit of highly concentrated cranberry juice in the prevention of repeated UTI episodes in uncircumcised boys (3).  The participants were 55 uncircumcised boys and 12 circumcised boys between the ages of 6 to 18 with a history of uncomplicated UTIs. The uncircumcised boys were divided into two groups in which group 1 drank 120mL of cranberry juice daily for 6 months while the second group drank a placebo juice. A third group was comprised of circumcised boys who also drank cranberry juice for 6 months. The results showed that group 1 had fewer recurrent UTI episodes when compared to both group 2 and group 3 (3).  There was also evidence that the preventative benefits were higher in uncircumcised boys than in circumcise ones (3).

Furthermore, a study looked at the effect of cranberry juice capsules on urinary tract infections in women post-surgery because the risk of UTIs is generally higher among women undergoing an elective gynecological surgery where a catheter is placed. 160 patients were randomized and given 2 cranberry capsules twice a day, about the same as 8-ounce servings of cranberry juice, for 6 weeks.  The results showed that the UTIs occurred lower in the cranberry treatment group compared to the placebo group (15/80 vs 30/80; p=0.008) and remained the same even after confounders were removed (4). 

Two randomized studies were done to assess how effective cranberries were in preventing bacterial UTIs in a population with pediatric neuropathic bladder.  Neither of these studies showed any effect on bacteria present in the urine in the population studied.  Another study in Finland studied 255 children who were being treated for UTIs.  The children were given either a placebo or cranberry juice for 6 months.  There was no timing difference found between the first incidence and the first recurrences of UTIs.  However, they found that the UTI incidence per person-year at risk was lower in those who received cranberries, and the number of days that a child was on antibiotic therapy was also lower in the children who received cranberries (5).  This indicates the potential for cranberries to help reduce the risk of UTIs in children and that further research needs to be done in this area.

  Cranberries Possibly Support a Healthy Prostate:

One study found that the prostate-specific antigen was reduced in 64 persons with prostate cancer who were given cranberry fruit powder for a period of 30 days (6).  However, more research still needs to be done, particularly involving clinical studies with human participants to fully assess the effect that cranberries can have on cancer.

  Cranberries Possibly Support Cardiovascular Health:

One trial assessing the effectiveness of cranberry juice on improving endothelial function and reducing cardiovascular risk found that there was a possible acute benefit, specifically with reducing artery stiffness (7).  However, no chronic effects were found.  On the other hand, another study done on 20 healthy females found that consuming cranberry juice for 2 weeks had no effect on blood or cellular antioxidant status or biomarkers related to heart disease (8).

  Cranberries Possibly Help Support Balanced Blood Sugar Levels:

A systematic review of the effects of cranberries on glycemic control found that consuming 240 mL of cranberry juice daily for 12 weeks had a promising effect on glucose control in patients with type 2 diabetes (9). 

Another study looked at the effects of strawberry and cranberry polyphenols (SCPs) on insulin sensitivity, glucose tolerance, insulin secretion, lipid profile, inflammation and oxidative stress markers in obese or overweight persons.  The experimental group of the study was given an SCP beverage that contained 333mg of SCPs daily. After 6 weeks, they found that insulin sensitivity in the participants had improved, but found it was not as effective for improving other cardiometabolic risk factors (10).

 

SAFETY

The research does not show any adverse effects of using cranberries in any amount (besides potential drug interactions). 

Interactions:

Moderate

  • The most commonly reported drug interaction with cranberry is with warfarin (11,12,13,14,15,16,17,18).  Some research concluded that there are no interactions between cranberry juice and warfarin but still states that patients should be warned about a potential interaction and should be closely monitored for any changes in INR and symptoms of bleeding (19,20).

Side-Effects:

  • The most commonly reported side-effects include: reflux, mild nausea, frequent bowel movements, headaches, elevation in blood glucose levels, and a cutaneous reaction (21).

 

REFERENCES

  1. Neto CC, Vinson JA. Cranberry. CRC Press/Taylor & Francis; 2011. http://www.ncbi.nlm.nih.gov/pubmed/22593931. Accessed February 3, 2018.
  2. Occhipinti A, Germano A, Maffei ME. Prevention of urinary tract infection with Oximacro®, a cranberry extract with a high content of a-type proanthocyanidins: A pre-clinical double-blind controlled study. Urol J. 2016;13(2):2640-2649.
  3. Wan K-S, Liu C-K, Lee W-K, Ko M-C, Huang C-S. Cranberries for Preventing Recurrent Urinary Tract Infections in Uncircumcised Boys. Altern Ther Health Med. 2016;22(6):20-23.
  4. Foxman B, Cronenwett AEW, Spino C, Berger MB, Morgan DM. Cranberry juice capsules and urinary tract infection after surgery: results of a randomized trial. Am J Obstet Gynecol. 2015;213(2):194.e1-8. doi:10.1016/j.ajog.2015.04.003
  5. Goldman RD. Cranberry juice for urinary tract infection in children. Can Fam Physician. 2012;58(4):398-401.
  6. Student V, Vidlar A, Bouchal J, et al. Cranberry intervention in patients with prostate cancer prior to radical prostatectomy. Clinical, pathological and laboratory findings. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub. 2016;160(4):559-565. doi:10.5507/bp.2016.056
  7. Dohadwala MM, Holbrook M, Hamburg NM, et al. Effects of cranberry juice consumption on vascular function in patients with coronary artery disease. Am J Clin Nutr. 2011;93(5):934-940. doi:10.3945/ajcn.110.004242
  8. Duthie SJ, Jenkinson AM, Crozier A, et al. The effects of cranberry juice consumption on antioxidant status and biomarkers relating to heart disease and cancer in healthy human volunteers. Eur J Nutr. 2006;45(2):113-122. doi:10.1007/s00394-005-0572-9
  9. Rocha DMUP, Caldas APS, da Silva BP, Hermsdorff HHM, Alfenas R de CG. Effects of blueberry and cranberry consumption on type 2 diabetes glycemic control: A systematic review. Crit Rev Food Sci Nutr. January 2018:1-13. doi:10.1080/10408398.2018.1430019
  10. Paquette M, Medina Larqué AS, Weisnagel SJ, et al. Strawberry and cranberry polyphenols improve insulin sensitivity in insulin-resistant, non-diabetic adults: a parallel, double-blind, controlled and randomised clinical trial. Br J Nutr. 2017;117(4):519-531. doi:10.1017/S0007114517000393
  11. Hamann GL, Campbell JD, George CM. Warfarin-cranberry juice interaction. Ann Pharmacother. 2011;45(3):e17. doi:10.1345/aph.1P451
  12. Mergenhagen KA, Sherman O. Elevated International Normalized Ratio after concurrent ingestion of cranberry sauce and warfarin. Am J Health Syst Pharm. 2008;65(22):2113-2116. doi:10.2146/ajhp080135
  13. Haber SL, Cauthon KAB, Raney EC. Cranberry and warfarin interaction: a case report and review of the literature. Consult Pharm. 2012;27(1):58-65. doi:10.4140/TCP.n.2012.58
  14. Grant P. Warfarin and cranberry juice: an interaction? J Heart Valve Dis. 2004;13(1):25-26.
  15. Rindone JP, Murphy TW. Warfarin-cranberry juice interaction resulting in profound hypoprothrombinemia and bleeding. Am J Ther. 13(3):283-284. doi:10.1097/01.mjt.0000178908.32892.2f
  16. Mohammed Abdul MI, Jiang X, Williams KM, et al. Pharmacodynamic interaction of warfarin with cranberry but not with garlic in healthy subjects. Br J Pharmacol. 2008;154(8):1691-1700. doi:10.1038/bjp.2008.210
  17. Paeng CH, Sprague M, Jackevicius CA. Interaction between warfarin and cranberry juice. Clin Ther. 2007;29(8):1730-1735. doi:10.1016/j.clinthera.2007.08.018
  18. Asher GN, Corbett AH, Hawke RL. Common Herbal Dietary Supplement-Drug Interactions. Am Fam Physician. 2017;96(2):101-107.
  19. Mellen CK, Ford M, Rindone JP. Effect of high-dose cranberry juice on the pharmacodynamics of warfarin in patients. Br J Clin Pharmacol. 2010;70(1):139-142. doi:10.1111/j.1365-2125.2010.03674.x
  20. Pham DQ, Pham AQ. Interaction potential between cranberry juice and warfarin. Am J Health Syst Pharm. 2007;64(5):490-494. doi:10.2146/ajhp060370
  21. Hisano M, Bruschini H, Nicodemo A C, Srougi M. Cranberries and lower urinary tract infection prevention. Clinics (Sao Paulo). 2012 Jun; 67(6): 661–667. doi:  10.6061/clinics/2012(06)18

See the Penn State Hershey Health Information Library entry for cranberry, the National Center for Complementary and Integrative Health entry for cranberry, the WebMD entry for cranberry, the RXList entry for cranberry, or the Michigan Medicine Health Library entry for cranberry for more information.